FR2499739A1 - SYSTEM FOR SELECTIVE TRANSMISSION OF ROAD INFORMATION - Google Patents

Abstract

THE INVENTION RELATES TO A SYSTEM FOR SELECTIVE TRANSMISSION OF ROAD INFORMATION. THE SYSTEM INCLUDES LOCATION TRANSMITTERS 2 DEFINING ROAD INFORMATION CELLS AND SENDING A CODE SIGNAL TO IDENTIFY ONE OF THESE CELLS, THE ITINERARY AND OR THE DIRECTION OF TRAFFIC FOLLOWED BY VEHICLES 8, TRANSMITTERS OF INFORMATION 12 TRANSMITTING ROAD INFORMATION MESSAGES PRECEDED BY ANALOGUE PREAMBLE TO THE CODE SIGNAL, ON-BOARD RECEIVERS 10 MOUNTED ON THE SAID VEHICLES DETECTING AND IDENTIFYING THE MESSAGES DESTINED TO THEM, THE CODE SIGNAL HAVING BEEN RECORDED AND RECORDED BY THE BOARDS PREVIOUSLY , THE IDENTIFICATION OF THE MESSAGES BEING COMPARED BY COMPARING THE PREAMBLE AUDIT SIGNAL CODE, AND DISTRESS TRANSMITTERS 14 MOUNTED ON THE SAID VEHICLES SENDING DISTRESS MESSAGES ANALOGUE TO THE SIGNAL CODE TOWARDS EMERGENCY RECEIVERS 16 LOCATED NEAR 18 EMERGENCY CENTERS .

Description

The present invention relates to a selective transmission system

information. This

  The purpose of the system is to communicate to the occupants of

  vehicles of emergency messages and / or information

  specific road sections of a section of road

and / or a direction of circulation.

  This system makes it possible, for example, to

  information concerning all the vehicles on

  on the same route and / or in the same direction

  information about all vehicles

  approaching them the neighborhood of an agglomeration or a

  crossroads, which information may indicate the presence

  it's a traffic jam, an accident, a deviation

  etc., or information concerning the transpor-

  such as information on bar-

thaw, etc.

  At present, the various known traffic information transmission systems are based on

  essentially on the selection of vehicles for

  by selecting an issuer issuing the said information. Of these systems, some allow

  to select a direction of circulation by means of

  so-called "roadside" systems. Such systems of

  roadside "have been described in the French patents

  No. 2,203,120, 2,207,279 and 2,222,710.

  In all known systems, the receiving zone or cell is defined by the radio coverage of the associated transmitter, even if the range of said transmitter can be modulated by

  interference caused by transmitters

  vironnants. This latter system has been described in a

  publication entitled "A proposed road traffic information

  services described in Reprinted from E.B.U.

  Review-Technical No. 166 (December 1977).

  These systems have a number

  disadvantages related essentially to their exploitation

  tion. In particular, these systems do not offer any flexibility of use and require, in order to be put in operation, that the infrastructure has been fully established throughout the territory considered or at least in a given region; this is due to the fact that the receiving zone or cell is defined by the radio coverage of the associated transmitter, the geographical position of the latter determining said zone. The object of the invention is precisely a system

  selective transmission of road traffic information

  putting a solution to these disadvantages. In particular

  the system of the invention, it is not necessary to

  to wait until all the infrastruc-

  its structure to begin the operational phase.

  nelle. More precisely, the invention

  object a system of selective transmission of information

including.

  a first set of transmitters defining, on a

  given territory, information

  each issuer of that first set being

  capable of transmitting a coded localization signal

  identifying one of the cells as being

  route and / or the direction of traffic followed by vehicles capable of moving in said cell; and a second set of emitters capable of transmitting,

  each, road information messages to

  the said vehicles, these messages being

  dice of a coded preamble analogous to said coded signal

  location to identify one of the

  said cells, the route and / or the direction of traffic

  followed by said vehicles; and - an onboard permanent standby receiver mounted on

each of said vehicles.

  These edge receivers consist of a first receiving subassembly adapted to receive the coded location signals, means for processing and storing said coded location signals, a second receiving subassembly able to receive traffic information messages and associated coded preambles, means for processing said preambles and

  means of identifying messages of

  trainings for each of said vehicles by

  paraison of said preambles to the last coded location signal stored in memory as said vehicles are likely to move in one of said cells, following a route and / or a direction

given circulation.

  The use of a coded preamble preceding

  traffic messages give the system

  transmission of the invention a great flexibility of use. In particular, it can be pointed out that this system is useful for the operating services to modify at will the said system by playing only on the said preamble, which allows a great selectivity in the traffic information messages. For example, the type of vehicle, as well as the language spoken by the driver, can be

  creation of an international system.

  It should be noted that some systems known to date used preambles or codes preceding the traffic information messages, but these codes concerned message start codes or emergency codes. These codes, unlike those

  of the invention, did not make it possible to select

  among the traffic information messages transmitted, the latter being received by all vehicles without any possible distinction between them. Such systems have been described for example in a French patent No. 2

  227 690 entitled "Disposition of transmission of

born. "

  According to a preferred embodiment of the invention,

  vention, each emitter of the first set, called locator transmitter, corresponding to a given cell, is placed on a portion of a traversing road

  the limits of this cell and close to these li-

  mites so as to materialize said cell, as well as

  on portions of roads crossing a crossroads

killed in said cell.

  The physical materialization of the traffic information cells makes it possible to locate vehicles that are in difficulty, for example

  damaged vehicles. It should be noted that the systems

  information transmission systems, known to date, did not consider this location

such vehicles.

  - This location of the damaged vehicles is linked to the fact that, according to the invention, the system of

  transmission includes, in addition, issuers of

  braid mounted on vehicles, a transmitter of

  by vehicle, likely to send messages of

  coded distress with a distress signal, the

  encoded localization code stored in

  receivers and fixed data stored in

  re characterizing each vehicle and a network of backup receivers capable of receiving and identifying said coded messages, these receivers of

  aid being arranged in the vicinity of

  responsible courses, each, of a group of cells.

  According to another preferred embodiment of

  the invention, the transmitters of the second set, called

  also transmitters of information, broadcast, broadcast

  averages, in amplitude modulation, the messages of

  road trainings and in frequency modulation or

  more precisely by displacement, frequency

  bules preceding said messages. Furthermore, transmitters may broadcast on the same frequency and in timeshare

  issuers, including radio

  have a common part, do not emit

  not simultaneously, on different frequencies.

  According to another preferred embodiment of the invention, the edge receivers further comprise means for storing fixed data characterizing the vehicles, on which said

  onboard receivers are mounted, and means

  the connection of the loudspeaker to said on-board receivers, this connection being made after identification of the traffic information messages intended for said on-board receivers. These edge receivers are

  more, associated, each, with an antenna and a

  may be those of an "auto-radio", ie

  say a classic radio receiver.

  Other features and benefits of

  the invention will emerge more clearly from the description which will

  follow, given purely for illustrative purposes and not

  mitative, with reference to the appended figures, in the

  which - Figure 1 shows schematically the selective transmission system of the invention as well as

  the arrangement of the different elements constitutes the

  killing; FIG. 2 diagrammatically represents the on-board equipment mounted on the vehicles to which the system of the invention is applied; and

6 2499739

  FIG. 3 schematically represents an example of

  differences in the system of invention

  tion. According to the invention, the French territory or the like is divided into a number of zones of variable dimensions, called information cells.

  road; some of these cells have been

  shown in Figure 1 which shows the arrangement on a region of said territory of the various elements 0 constituting the selective transmission system of the invention. The boundaries of these cells, represented

  in dashes, are defined by means of a first

  seem to be issuers, also known as local transmitters.

  tion. These location transmitters, referenced 2, are located on the portions of roads 4 crossing the boundaries of the traffic information cells, in this case the transmitters are referenced 2a, and on the portions of roads 4 crossing a junction such as 6

  located in one of the cells, in the other case

  said transmitters bear reference 2b. The localization transmitters 2a physically, in fact,

  said traffic information cells.

  Location 2 transmitters are likely to

  transmit a coded localization signal, an example of which will be given later,

  to identify one of the traffic information cells

  res, the route and / or direction of movement followed by vehicles such as 8 moving in said cell. Each of these vehicles, represented in the form of rectangles, is associated with an arrow indicating

  the direction of circulation followed by said vehicle.

  These location transmitters 2 which can

  electromagnetic loops, radio beacons

  Very high frequency (VHF) and frequency modulation (FM) power, laser or infra-red transmitters, etc. have extremely small radio frequency ranges, that is to say between 10 and 40 meters, and not contiguous and emit continuously in a repetitive way. A vehicle 8 traveling on roads 4 equipped with location transmitters 2 is provided with a so-called edge receiver, shown schematically by a cross bearing the reference 10; this receiver is, in fact, part of a whole called equipment on board which one

  will later give the structure and the functioning

  is lying. These edge receivers 10, in permanent standby,

  are likely to receive coded signals from

  calification issued by the localization transmitters 2 and

  remember the last coded local signal

  received. For example, leaving a cell

  road information to enter into the follow-

  te, the vehicle considered will first meet the transmitter location 2a of the cell that has just crossed, then that of the cell it addresses and

  of which he will keep the coded signal of localization in

  until he leaves the cell.

  It is the same when said vehicle 8,

  meeting a crossroads 6 located in one of these

  lules, change of route and / or direction of movement

tion.

  In addition, these edge receivers 10 are sus-

  able to detect red information messages

  issued, in the case of the French territory, to

  Regional Traffic Information Centers (CRICR) and the National Road Information Center (NIRC) through a second

  set of issuers, also known as transmitters of information

  mation. One of these issuers of information was

  shown in Figure 1 and has the reference 12.

  These information transmitters 12 transmit either, on the same frequency and in timeshare,

  two issuers whose radio coverage

  Electrical devices comprise a common partle do not simultaneously speach either, on different frequencies.

  In the latter case, the frequency setting of the receiver

  driver 10 is then automatically performed upon receipt of the coded location signals transmitted by

  location transmitters; these localization signals

  order, then, the selection of the frequency

  of the bor.d receptor.

  formations 12 are for example wave transmitters

  average, that is, emitting in a range of frequencies

  quence ranging from 500 to 1500 kicohertz (kHz).

  Each of these information transmitters 12

  transmits, in amplitude modulation, messages of

  road trainings intended for a certain number of cells, the number of these cells constituting the zone

  radio coverage of said transmitter. These mes-

  information is preceded by a preface

  coded ambule, analogous to the coded location signal transmitted by the location transmitters 2, defining a cell, or a group of cells, the route and possibly the direction of circulation followed by the

  vehicles moving in the one or more cells.

  These preambles emitted in frequency modulation or more

  precisely by frequency shift (FSK)

  to say in Anglo-Saxon literature Frequency Shift

  Keying, thus allow the on-board receivers to

  information messages that

  are intended, this identification being made in

  paring said preambles to the localized coded signals

  previously stored in those receivers

operators.

  In addition, these preambles may define a

  type of vehicle and / or a language spoken by

  pants of certain vehicles in the case of transmission

  very selective information messages.

  In addition, each message of red-

  is followed by an end-of-message code, transmitted in frequency modulation or more precisely in FSK, in-

  indicating the end of said traffic message.

  In the case where the number of location transmitters 2 is sufficiently large (see embodiment example of the system), we can consider equipping vehicles with a distress transmitter operating for example in frequency modulation. These transmitters

  distressed by a round bearing the reference

  this 14, are, in fact, part, as the receiver of

  board 10, on-board equipment. These issuers of

  braid 14, all operating on the same frequency and

  shortwave, that is to say in a range of frequencies

  range from 3 to 30 megahertz (MHz), transmit signals consisting of a distress signal,

  coded location signal stored in memory previously

  and stored data characterizing each vehicle and / or characterizing the spoken language.

  by the occupants of the said vehicle. Fixed data

  characterizing each vehicle are for example the type

  vehicle, its mark, its color, its

matriculation, etc.

  Messages from distress messages can

  may be triggered manually by one of the occupants of the vehicle in difficulty, for example by means of a push button of conventional type

  or, following a violent shock resulting from an accident

  tooth, by means of an inertia shock detector, the

  said detector can be made by the battery of said vehicle through a buffer accumulator. In case the connection with the battery of the

  vehicle would have been interrupted during the shock, the

  distress transmitter 14 will then be ensured

  for a sufficient time by the accumulator. The emis-

  distress messages causes the operation

  noise, installed in the said vehicle and intended to warn the occupants of the vehicle. In addition, in case of false maneuvers or untimely triggering by the shock detector, a correction signal similar to the distress message

  previously issued may be sent by the occupants of-

  said vehicle for example by means of a push button

of classic type.

  These distress messages are likely to be received by a network of emergency receivers, schematized by a rectangle bearing the reference 16,

  in the vicinity of relief centers

  each of a group of information cells

  road. These emergency receivers 16, after identification

  application or decoding of the distress messages, can store and display said messages and trigger a visual and / or audible alarm located in the emergency center concerned. One of these rescue centers has been shown in Figure 1 and is

  18. Similarly, the limits of a zone of se-

  course, corresponding to this emergency center 18 and

  corresponding to a given number of traffic information cells, ie four cells in FIG. 1, have been schematized in solid lines in said figure. These rescue centers 18 may be, for example, as regards the French territory, the stations of the

  Emergency Medical Assistance (EMS) services and

  these regional emergency medical (SMUR) barracks

firefighters, etc ...

  In Figure 2, there is shown the equipment

  vehicles consisting mainly of

  on-board receiver 10 and distress transmitter 14.

  The on-board receiver 10 is associated with a

  antenna 20 and a loudspeaker 22 provided with an amplifier

  24. This antenna 20 and this high-par-

  22 may be those of a conventional or radio-type radio receiver 26, if the vehicle

siderate has one.

  In general, the on-board receiver consists of two reception subsystems and

  a set of data processing.

  The first of these two subsets

  ception, called locating receiver and comprising

  reference 28, is likely to receive

  coded localization codes issued by the transmitters of

  2. The nature of these localization receptors

  28 depends on the nature of the issuers of

  2. If the location transmitter 2

  transmits in frequency modulation, said receiver of

  Calibration 28 will operate in frequency modulation.

  Each received coded location signal will then be demodulated by means of a demodulator as processed and then processed in a data processing system 32 and

  finally memorized in a memory 34. The reception of a

  encoded location signal will automatically erase

  the previously stored coded signal.

  The second subassembly of reception,

* peeled information receiver and featuring reference

  this 36, is likely to receive the messages of in-

  road trainings as well as the coded preambles preceding said messages, these messages and preambles

  being issued by the issuers of information.

  encoded route of each traffic message,

  frequency modulation, will first be demo-

  dithered by means of a demodulator such as 38, preceded by a passband filter 37, and then processed in a

pretreatment 40.

  The coded preamble will then be compared by means of a

  parator 42 to the coded location signal stored in the memory 34. If a part of the coded preamble is identical to the coded location signal. memorized, the audition of the traffic information message may

take place.

  The wiretapping, ie the connection of the speaker 22 to the information receiver 36, may

  be done manually by the occupants of the vehicle.

  considered, said occupants having been informed

  by means of an audible and / or visual alarm,

  using a switch. The system of

  command for wiretapping and switching

  whether or not the loudspeaker 22 is

by the device 44.

  In the case where the loudspeaker 22 and the antenna

  are not those of a car radio 26, the device 44 interrupts the listening of said car radio, if it is in operation, and connects the speaker and the low frequency stages of said car radio, the receiver of board being then integrated therein, so that the traffic information messages can be heard by the occupants of said vehicle. When the

  information message is completed, the provision of

  44 reconnects the loudspeaker 22 on the car radio

  26 and the occupants of the vehicle can again

  the previously interrupted radio program.

  The reconnection or reconnection of the loudspeaker 22 on the car radio 26 is performed after the message end message that follows the traffic information message.

  was detected by a detector 46.

  In the event that this is the end of the message

  may not be detected, a time may be

  internalization of the on-board receiver, this time

  a few tens of seconds, being

  killed by means of the device 48 provided for this purpose.

  The data processing system describes

  above, that is to say, the means by which

  coded preambles and coded signals

  location and the memorization of the said

  coded localization codes is constituted, moreover,

  memory 50 containing the fixed data

  each vehicle, that is to say the type of vehicle

  the, its mark, its color, its registration number

  etc., as well as the language spoken by

pants of the said vehicle.

  In the case where the traffic information messages transmitted concern only one type of vehicle (road transport operators) and / or vehicles whose occupants speak a certain language, the coded preamble preceding said road information message then comprises, in more than the part corresponding to the coded location signal a corresponding part

  to these fixed data stored in the memory 50.

  me previously, the hearing of the traffic information message, for a type of vehicle and / or a certain

  language, is done after comparing by comparison

  42 the corresponding part of the preamble to the

fixed data stored in 50.

  As we saw earlier, a vehicle is

  in difficulty can send a message

  coded braid comprising the coded location signal stored in the memory 34 and the fixed data characterizing said vehicle stored in the memory

  50. This distress message, in order to be issued in modula-

  frequency, should be modulated by means of a

  such as 52. Reference 54 represents one of the means for triggering the transmission of said

  distress message, one of these means being, for example,

  the inertia shock detector and the reference 56 the buzzer indicating to the occupants of said vehicle

  the transmission of said distress messages.

  Practically: the memory 34 and the memory

  re 50 can be permanently supplied by the battery of the vehicle on which the on-board equipment is installed, the rest of said equipment being put on standby

from the establishment of the contact.

  Figure 3 shows the differences between

  coded signal formats used in the system.

  transmission, according to the invention. The first form

  mat bearing the reference t- represents the coded location signal, the second format bearing the reference p represents the coded preamble sent before the traffic information messages and the third format bearing the reference d represents the distress message. These three formats A d are preceded by a start code making it possible to identify them for example by a code LL representing the start code for the coded identification signal e, PP for the coded preamble 2 and DD for the message of distress d. These different formats are then constituted for example by a character E.

  one character Z, two characters CC, two characters

  II and S respectively

  the number of the issuer of information used, if any,

  for the selection of the tuning frequency of the on-board receiver 10 and in particular of the information receiver 36 when the information transmitters transmit on different frequencies, the number of

  the emergency zone, the cell number, the route

  and the direction of traffic followed by the vehicles

  moving in said cell.

  In the case of transmission of messages more

  the second signal p, corresponding to the preamble

  coded bule, includes two additional characters, a T character and an L character respectively

  the type of vehicle and the language spoken by

pants of the said vehicle.

  N -15 Regarding, the third signal of

  corresponding to the distress message, this one

  takes, in addition to the two characters T and L, two characters

  additional CO indicators indicating, for example, the

  the vehicle, its color or its registration number, these characters allowing the identification by

  the emergency centers of the said vehicle in the event of

  tooth, and a DD code corresponding to the distress signal sent by the distress transmitters.

  In addition to these three coded signals, we have

  presented a fourth signal with the reference f. This signal represents the end of message signal

  after the transmission of the traffic information messages

res.

  We will now give an example of reali-

  tion of the transmission system of the invention

  for example in French territory.

  First of all, it should be noted that the number of traffic information cells as well as their size depend solely on the number of messages that one

  wishes to emit as well as the level of selectivity

  said messages. Consequently, the number of location transmitters, the number of information transmitters, as well as the number of emergency centers can be modified according to the number of said cells. In addition, the number of location transmitters depends on

their radio range.

  For example, for issuers of localization

  with a radio frequency range of 30

  very (m), their mininum spacing being then 150

  meters (m), the reception of coded localization

  issued by those issuers may take place at

  least once by a vehicle moving at a distance

  140 kilometers per hour (km / h) while ensuring

  sufficient protection vis-à-vis other

  encoded location codes issued by neighboring location transmitters. This radioelectric range

  as well as the spacing between two local transmitters

  can be reduced depending on the speed of

  ximal authorized for said vehicles, that is to say for a speed of 90 km / hg the radio range of said location transmitters may be 20 m and the spacing between two locators of m. That said, in France, we plan to install

  a pair of location transmitters every five ki

  kilometers (Km) or 20,000 pairs per 100,000 km of

  roads, 10 issuers of road traffic information

  timeshare in 3 groups, as well as 500

emergency receivers.

Claims (25)

CLAIMS I   1. System of selective transmission of information   characterized in that it comprises:   a first set of transmitters defining, on a   given territory, information   each transmitter (2a, 2b) of that first set   being able to emit a coded localization signal   (t) to identify one of the   lules, the route and / or direction of traffic   screwed by vehicles (8) capable of moving in said cell;   a second set of transmitters (12) able to transmit   each, of the traffic information messages intended for said vehicles (8), these messages being   preceded by a coded preamble OP) similar to that   encoded localization code (t) for identifying   proud, one of said cells, the route and / or the direction of circulation followed by said vehicles (8); and   an on-board receiver (10), in permanent standby,   each of said vehicles, comprising a first   first receiving subassembly (28) adapted to receive the coded signals of localization (>), means   allowing the treatment (30, 32) and the setting   moire (34) of said coded location signals a   second receiving subassembly (36) able to receive   see the associated traffic information messages and coded preambles (2), means for processing (37, 38, 40) said preambles and means for identifying (42) information messages for each of said vehicles (8) by comparing said preambles (p) with the last coded location signal (t) stored in memory while said vehicles (8) are susceptible to   move in one of said cells, following a   and / or a given direction of circulation.   2. Transmission system according to the   cation.1, characterized in that the coded preambles (p) allow, in addition, the selection of the type of   vehicles and / or the language spoken by the occupants said vehicles (8).   3. Transmission system according to any one   shell of claims 1 and 2, characterized in that   moreover, means (46)   indicate the end of the traffic information messages. res.   4. Transmission system according to any one   one of claims 1 to 3, characterized in that   it includes, again, distress transmitters (14) mounted on the vehicles, a distress transmitter by   vehicle, capable of issuing messages of de-   braid coded (d) having a distress signal (DD), the coded location signal (<) stored in memory (34) in the on-board receivers, and fixed data   put (T, CO in memory (50) characterizing each   hicle as well. a network of emergency receivers (16)   able to receive and identify those messages   coded systems, these standby receivers being arranged at   neighborhood of rescue centers (18) responsible, each one of a group of cells.   5. Transmission system according to the   cation 4, characterized in that the distress message   (d) identify the language spoken by the occupants pants of said vehicles (8).   6. Transmission system according to any one   conque of claims 4 and 5, characterized in that   all the distress transmitters (14) transmit in modula-   frequency and on the same frequency.   7. Transmission system according to any one   conque of claims 4 to 6, characterized in that   the distress transmitters (14) broadcast on   your. 8. Transmission system according to any one   conque of claims 4 to 7, characterized in that   the vehicles (8) are provided with an inertia shock detector (54) which triggers the distress transmitters (14).   9. Transmission system according to any one   of claims 4-7, characterized in that   the distress transmitters (14) are triggered manually LEMENT.   10. Transmission system according to any one   conque of claims 4 to 9, characterized in that   the vehicles are equipped with a sound system (56) which is   triggered by the transmission of distress messages.   11. Transmission system according to the   10, characterized in that the vehicles (8) are   equipped with a means of transmitting in case of false maneuver   accidental tripping of the transmitter (14),   a correction message similar to the message of is.   12. Transmission system according to any one   conque of claims 4 to 11, characterized in that   the emergency receivers (16) comprise means for decoding the distress messages, means for   storage and display means of said mes-   and may sound an audible alarm and / or   located in the emergency centers concerned. born (18).   13. Transmission system according to any one   conque of claims 1 to 12, characterized in that   the emitters of the first set (2), corresponding to a given cell, are placed on the road portions (4) crossing the boundaries of this cell and close to these limits so as to materialize said   cell, as well as on the portions of roads (4)   pouring a junction (6) located in said cell.   14. Transmission system according to any one   conque of claims 1 to 13, characterized in that   the emitters in the first set (2) have   reduced radioelectric range, not contiguous.   15. Transmission system according to the   cation 14, characterized in that the radio-electric range   of the transmitters of the first set (2), is taken between 10 and 40 meters.   - 16. Transmission system according to the   Claims 1 to 15, characterized in that the coded location signal (t) makes it possible to adjust the tuning frequency of the second reception subassembly <36)   constituting the edge receiver (10).   17. Transmission system according to any one   conque of claims 1 to 15, characterized in that   the transmitters of the second set (12) transmit on the same frequency and in timeshare, said transmitters   with radio covers that include both common parts.   18. Transmission system according to any one   conque of claims 1 to 16, characterized in that   the transmitters of the second set (12) transmit on different frequencies.   19. Transmission system according to any one   conque of claims 1 to 18, characterized in that   the transmitters of the second set (12) transmit, on medium waves, the traffic information messages   amplitude modulation and the preceding preambles (2)   said messages in frequency modulation.   20. Transmission system according to any one   conque of claims 1 to 19, characterized in that   the edge receivers (10) are associated with an antenna (20) and a loudspeaker (22) and furthermore comprise means (50) for storing fixed data characterizing the vehicles on which said edge receivers are mounted, and means (44)   putting the speaker connection (22) to said reeds   receivers, this connection being made after identification of the traffic information messages   for said edge receivers (10).   21. Transmission system according to the   20, characterized in that the antenna (20) and the   loudspeakers (22) are those of a car radio (26).   22. Transmission system according to any one   of claims 20 and 21, characterized in that   the means (44) for connecting the loudspeaker   speaker (22) consist of an audible and / or visual alarm whose operation indicates to the occupants of said vehicles (8) to connect said loudspeaker (22).   23. Transmission system according to any one   of claims 20 and 21, characterized in that   the means (44) for connecting the loudspeaker   speaker (22) are constituted by a switch enabling   both automatic connection of said speaker (22).   24. Transmission system according to the   cation 21, characterized in that the means (44)   connecting the loudspeaker (22) are   of a switch allowing the automatic connection of   said speaker (22) as well as the connection of the low frequency stages of the car radio (26), said   edge receivers (10) are then integrated into this this.   25. Transmission system according to any one   conque of claims 4 to 24, characterized in that   the coded location signals (t), the preambles   coded (R) and coded distress messages (d)   take a different start code (LL, PP, DD)   each other and allowing their identification.